This invention relates to drug delivery. More particularly, this invention relates to compositions and methods for oral delivery of poorly absorbed drugs.
The gastrointestinal tract, particularly the small intestines, is the primary site for absorption of nutrients and most bioactive agents. To accommodate the processes of absorption, the amount of surface area in the small intestines is enlarged due to the presence of villi and microvilli. However, before a bioactive compound is transferred from the intestinal lumen to the blood, the compound may be subject to degradation or deactivation by the various components of the lumen. Moreover, the compound may be required to pass through several barriers to absorption, such as the mucous layer and the intestinal brush-border membrane. Many compounds pass these barriers easily, but there are many nutrients and bioactive agents to which these barriers represent a serious obstruction.
There are many factors that can affect the oral bioavailability of drugs in the gastrointestinal tract. They include, for example, factors relating to the drug itself, such as active or passive transport, water solubility, molecular weight, chemical stability, ionization, pH, and the like; factors relating to chemical processes, such as deamination, hydrolysis (or ionization), oxidation, racemization, beta elimination, disulfide exchange, and the like; and factors relating to physical processes, such as aggregation, precipitation, denaturation, adsorption, and the like.
While prior art products and methods of use thereof are known and are generally suitable for their limited purposes, they possess certain inherent deficiencies that detract from their overall utility in delivering poorly absorbable drugs by the oral route. Namely, these prior art products and processes fail to increase intestinal absorption of the drugs while preventing physical and/or chemical decomposition or inactivation of the drugs.
In view of the foregoing, it will be appreciated that providing compositions and methods for efficient oral delivery of poorly absorbed drugs would be a significant advancement in the art.